I used CrystalDiskMark to test the SSD. I want use it for my Ceph cluster. I know some applications make Ceph write many small blocks. I know that Ceph dont allow caching. I turned off caching for the SSD. I set CrystalDiskMark to 4KB random read and write. One thread one queue. The result was for read 68MB/s. That is bad. For write it was 8MB/s. 
. Maybe i should not have bought the SSD. They say you must use PLP SSDs for Ceph.
For random 4KB 16 threads 32 queues. The result for read was 1700MB/s. Not so bad. For write it was 340MB/s. I expected better.
The read will probably be good enough. The write is too slow. I expect to get something between 1 thread and 16 threads for Ceph.
